The present invention relates to a surgical microscope system, and more particularly, to a surgical microscope system for performing a microscopic surgical operation.
In recent years, the so-called microsurgery of performing a microscopic surgical operation while observing with a microscope is widely used in public. The so-called microsurgery, which makes it possible to perform a high precision microscopic surgical operation, has greatly contributed to the wide fields including the ophthalmology, neurosurgery, otorhinolaryngology, plastic surgery and the like. Particularly, there has been an increasing demand in the field of ophthalmology for performing a cornea operation by measuring a radius of curvature of the cornea and controlling the extent of a suturing operation in accordance with the measured value so as to prevent the corneal astigmatism from occurring after the operation. To meet the demand, for example, Japanese Laid-Open Publication No. Sho 59/1984- 155232 discloses an apparatus for measuring the cornea configuration which is mounted on a surgical microscope in a unitary manner therewith. The apparatus will be described hereinafter with reference to FIGS. 1 to 4.
In FIG. 1, a surgical microscope includes a body 1, an objective lens 2, a light source 3 such as a circular fluorescent lamp for illuminating a projection index 4. When the index 4 is projected onto a cornea Ec of an eye to be measured, a reflected image 4' (virtual image) of the cornea Ec is formed to the index 4 by the convex-mirror action of the cornea Ec. The reflected image 4' varies in its size in accordance with a curvature of the radius of the cornea Ec. When the cornea Ec has regular astigmatism, the reflected image 4' is in an elliptic form and when the cornea Ec has irregular astigmatism, the reflected image 4' is in an irregular form. For this reason, it is possible to determine a surface configuration of the cornea Ec by measuring the reflected image 4' thereof.
An optical path change member 5 is provided in an optical system for measuring a cornea configuration which has a reflecting surface oblique to the exterior of an observation optical system in a space between the binocular observation optical paths. The optical path change member 5 is fixed adjacent to the objective lens 2 to the microscope body 1.
Reference numeral 6 is an objective lens of the cornea configuration measuring optical system. A diaphragm plate 7 is disposed adjacent to the rear side focus of the objective lens 6. A deflecting prism 8 is fixed adjacent to the rear side of the diaphragm plate 7. The diaphragm plate 7 has, for example, five small trough-holes at its center portion, as shown in FIG. 2. The deflecting prism 8 is in such a form as five prism pieces of the wedge type are put together in a unitary form, as shown in FIG. 3. The through-hole openings of the diaphragm plate 7 agree with the respective centers of the prism pieces of the deflecting prism 8. Projecting light beams from the reflected image 4' incident upon the objective lens 6 are divided into five beams through the openings of the diaphragm plate 7 and the deflecting prism 8. The five beams are then reflected by a reflecting mirror 9 to form images respectively upon light receiving surfaces of detector elements 10, such as one dimensional photodiode array. The five detector elements 10 are arranged respectively at positions where projected images 4" are formed to the reflected image 4', for example, as shown in FIG. 4.
With the cornea configuration measuring device of the structure just described above, a measuring switch (not shown) is turned on and at the same time a configuration of the reflected image 4' is detected by the detector elements 10. The detected signals are electrically amplified and calculated by a signal operating circuit (not shown) to determine the major and minor axes of an ellipse and the elliptic axes for the reflected image 4'. From these data a radius of curvature, a degree of astigmatism, an axial angle of astigmatism and the like are determined and displayed. When the cornea reflected image is not circular or elliptic because of irregular astigmatism, radii of curvature are determined and displayed respectively for meridional directions of the cornea.
Since a conventional apparatus is constructed as described above, it is necessary to provide a light source only for the cornea configuration measurement in addition to an illumination light source for observation or photographing. In addition, switches are provided for respective light sources. As a result, the apparatus becomes bulky, expensive and complicated in operation. Furthermore, since it is very troublesome to remove the measuring device from the apparatus after the cornea configuration measurement is completed, an operation must be performed with the measuring device attached to the apparatus between the objective lens and eyes to be measured, resulting in difficulty in operation, that is very dangerous.